Calcined Mg–Fe hydrotalcite-like compounds (HTLs), hydrotalcite-like oxides (HTOs), have shown potential performance for removing hydrochloric acid (HCl) from flue gas at medium-high temperatures. The adsorption of HCl on Mg–Fe HTOs was studied from 350 to 650 °C. The average removal efficiency of HCl on Mg–Fe HTOs is affected primarily by temperature-dependent structural changes. Structural changes in pristine and calcined HTL samples were characterized using various analytical techniques. The pyrolysis kinetics of Mg–Fe HTLs were also studied using Kissinger–Akahira–Sunose and Flynn–Wall–Ozawa methods at temperatures ranging from room temperature to 700 °C. The layered structure of HTLs was maintained at 255 °C, where the activation energy of decomposition was approximately 35–38 kJ·mol–1. At 350 °C, the removal efficiency of HCl adsorption on the HTOs was as high as 92.4%. Upon heating to 495 °C, the activation energy was 65–70 kJ·mol–1, and the HTL structure was destroyed by the decomposition of carbo...